4 Answers
4

In some non-tertian forms of music a "chord" created by a series of the same intervals (such as fourths) is described systematically by the specific interval and the number of pitches used. This chord would be described as two quartal triads (quartal describing the interval of the fourth and triad because three different notes are used).

These chords are openly inverted and have no real system of usage in terms of common practice. I am not including the second "A natural" because it is a repeated note most likely for emphasis. It seem the chord is built on "A" as a root note.

edit: If you reorganize the notes in this chord you wind up with two sets of three perfect fourths (working under the assumption that "A(low)" means Ab). If both A's are intended to be natural I would posit that this is an Ebmaj7#9 (Eb-G-Bb-D-A)

I see. But the fact that these sets are half a tone apart should be very relevant, shouldn't it?
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GauthierMar 27 '12 at 18:48

1

Note that #9 in a Eb chord is F#. A would be #11 or #4, and the chord would then be a lydian chord. But having the #11 at the bottom of the chord is a bit strange. On the other hand, this is arpeggiated.
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GauthierMar 27 '12 at 18:52

man, I am really failing on this. I meant to write 11 : ) I suppose the context would help alot with analyzing this chord.
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StephenMar 27 '12 at 21:28

Seems to me that this is a chord built on stacked perfect fourths with added neighbor notes for embellishment.

A to D is a perfect fourth. D to G is a perfect fourth.

The A#, D#, and A/Ab (I'm assuming by low you mean flat) are neighbor notes -- being that they are one half-step higher than their counterparts -- and do not play a role in the actual naming of the chord.

Composers will add neighbor notes and passing notes, which are dissonant to the main chord or harmony, as a way to add embellishment, tension, and interest.

The iwato scale is a musical scale that is similar to the Locrian mode
(spelled 1 b2 b3 4 b5 b6 b7), seventh mode of the major scale,
different in that it has no 3rd or 6th notes, thus making it
pentatonic. It spelling is therefore 1 b2 4 b5 b7. It is used in
traditional Japanese music for the koto.

A scale is not a chord, but since the sequence is played in "arpeggio form", I believe this is relevant.

As a quizz question, I think the probabilty of Iwato being part of the answer is significant.

Basic triads are one thing, but with more complex chords, in functional haromony, a group of notes can only truly be identified as a chord if they are examined in the context of the chord progression in the musical passage where you find it. There's not much point in trying to give one group of notes a name in isolation. The same group of notes may have different chord names depending on their use in different contexts.

Guitarists tend not to realize this, because guitarists tend to look at a chord as a particular "shape" of fingers on the fretboard, and they want to give one "shape" a name. But composers, music theorists, and other instrumentalists, even piano players, don't think this way.